Field
Embodiments of the present invention relate to the field of clinical diagnostic tools.
Background
Given the complexity of the automation of molecular testing and immunoassay techniques, there is a lack of products that provide adequate performances to be clinically usable in near patient testing settings. Typical molecular testing includes various processes involving the correct dosage of reagents, sample introduction, lysis of cells to extract DNA or RNA, purification steps, and amplification for its subsequent detection. Even though there are central laboratory robotic platforms that automate some of these processes, for many tests requiring a short turnaround time, the central laboratory cannot provide the results in the needed time requirements.
However, it is difficult to implement systems in a clinical setting that provide accurate, trustworthy results at a reasonable expense. Given the complicated nature of various molecular testing techniques, the results are prone to error if the testing parameters are not carefully controlled or if the environmental conditions are not ideal. For example, existing instrumentation for PCR techniques has experienced high entry barriers for clinical diagnosis applications due to the background generated by exogenous sources of DNA. In the case of specific tests of pathogens, the predominant source of contamination is a result of previous reactions carried out in pipettes, tubes, or general laboratory equipment. Additionally, the use of molecular techniques for detection of microbial pathogens can produce false negatives. The false negatives may result from, for example: improper disposal of agents that inhibit the Polymerase Chain Reaction (PCR) such as hemoglobin, urine or sputum; inefficient release of DNA from cells; or low efficiency in extraction and purification of DNA or RNA.
The fact that molecular techniques have exceptional sensitivity levels at concentrations lower than the previous reference methods makes it rather difficult to obtain clinically relevant conclusions, while avoiding erroneous calls with false positives. To minimize this problem, especially for the detection of pathogen microorganisms, tests should have quantification capability. It has therefore become increasingly necessary to perform multiplexed assays and arrays of tests to consolidate enough data to make confident conclusions. As an example, one of the main limitations of existing PCR-based tests is the inability to perform amplifications of different target genes simultaneously. While techniques such as microarrays provide very high multiplexing capacity, their main limitation is the low speed in obtaining the results, which often have no positive impact on patient management.